Valve prosthesis and method for delivery

ABSTRACT

Heart valve prostheses are provided for replacing a cardiac valve. The heart valve prosthesis includes a self-expanding frame including a first portion and a second portion. In the collapsed configuration, the first portion is positioned adjacent to the second portion. In the expanded configuration, the first portion moves to be positioned within an interior area of the second portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to an artificial heart valve frame.More specifically, the present invention is directed to an artificialvalve prosthesis.

2. Background Art

The mitral valve is a functional organ composed of multiple dynamicallyinterrelated units. During cardiac cycle, the fibrous skeleton, theanterior and posterior leaflets, the papillary muscles, the chordaetendinea, and the ventricular and atrial walls all interplay to render acompetent valve. The complex interaction between the mitral valve andthe ventricle by the subvalvular apparatus (the papillary muscles andthe chordae tendinea) is essential in maintaining the continuity betweenthe atrio-ventricular ring (which is part of the fibrous skeleton of theheart) and the ventricular muscle mass, which provides for the normalfunctioning of the mitral valve.

Cardiac valves, including the mitral valve, exhibit two types ofpathologies: regurgitation and stenosis. In the case of the mitralvalve, regurgitation is the abnormal leaking of blood from the leftventricle, through the mitral valve, and into the left atrium, when theleft ventricle contracts. Stenosis is the narrowing of the orifice ofthe mitral valve of the heart. Regurgitation is the more common of thetwo defects. Either defect can be treated by a surgical repair. However,surgical procedures can lead to an interruption of the mitralannulus-papillary muscle continuity, which accounts for changes ingeometry mechanics and performance of the left ventricle. These problemsare lessened by the emerging techniques for minimally invasive mitralvalve repair, but still many of those techniques require arresting theheart and funneling the blood through a heart-lung machine, which canalso be traumatic for patients.

Under certain conditions, the cardiac valve must be replaced. Standardapproaches to valve replacement require cutting open the patient's chestand heart to access the native valve. Such procedures are traumatic tothe patient, require a long recovery time, and can result in lifethreatening complications. Therefore, many patients requiring cardiacvalve replacement are deemed to pose too high a risk for open heartsurgery due to age, health, or a variety of other factors. These patientrisks associated with heart valve replacement are lessened by theemerging techniques for minimally invasive valve repair, but still manyof those techniques require arresting the heart and passing the bloodthrough a heart-lung machine.

In addition, valve replacement can create additional problems includinglimitation of the mitral flow during exercise due to a small effectiveorifice area and high cardiac output imposed by a smaller sizeartificial valve. Further, the rigid structure of an artificial valveprevents the physiologic contraction of the posterior wall of the leftventricle surrounding the mitral annulus during systole. Also,myocardial rupture can result from excision or stretching of thepapillary muscle in a thin and fragile left ventricle. Additionally,chordae rupture can also occur due to the chordae rubbing against theartificial valve over time, leading to increased heart wall stress. Ithas been shown that severing the chordae can lead to a 30% reduction inchamber function. Thus, mitral valve replacement has a high mortalityrate in very sick, chronic heart failure patients.

The chordae tendinea, which connect the valve leaflets to the papillarymuscles (PM) act like “tie rods” in an engineering sense. Not only dothe chordae tendinea prevent prolapse of the mitral valve leafletsduring systole, but they also support the left ventricular muscle massthroughout the cardiac cycle. To function adequately, the mitral valveopens to a large orifice area and, for closure, the mitral leaflets havean excess surface area (i.e. more than needed to effectively close themitral orifice). On the other hand, systolic contraction of theposterior ventricular wall around the mitral annulus (MA) creates amobil D-shaped structure with sphincter-like function which reduces itsarea by approximately 25% during systole, thus exposing less of themitral leaflets to the stress of the left ventricular pressure and flow.

It has been long postulated that the structural integrity of the MA-PMcontinuity is essential for normal left ventricular function. Recentevidence supports the concept that preservation of the subvalvularapparatus with the MA-PM continuity in any procedure on the mitral valveis important for the improved long-term quality and quantity of lifefollowing valve replacement. Maintaining the MA-PM continuity, thus,appears to provide a substantial degree of protection from thecomplications associated with valve replacement.

Efforts have been focused on percutaneous transluminal delivery ofreplacement cardiac valves to solve the problems presented bytraditional open heart surgery and minimally-invasive surgical methods.In such methods, a valve prosthesis is compacted for delivery in acatheter and then advanced through a patient's vasculature to the heart,where the prosthesis is then deployed in the native valve annulus.

Therefore, what is needed is a mitral valve prosthesis and method ofimplantation that minimizes the traumatic impact on the heart whileeffectively replacing native leaflet function. A consistent,reproducible, and safe method to introduce a prosthesis into the mitralposition in a minimally invasive fashion could be attractive fornumerous reasons: a) it can treat both functional and degenerativemitral regurgitation (MR); b) it can treat mitral stenosis; c) it canoffer a remedy to inoperable patients, high risk surgical patients, andthose that cannot tolerate bypass; d) it can allow a broad range ofpractitioners to perform mitral valve procedures; and/or e) it canenable more consistency in measuring outcome.

BRIEF SUMMARY OF THE INVENTION

Provided herein are mitral valve prostheses and methods for implantingthe prostheses in the heart. The prostheses generally include aself-expanding frame and two or more support arms. A valve prosthesis issutured to the self-expanding frame. Each support arm corresponds to anative mitral valve leaflet. At least one support arm immobilizes thenative leaflets, and holds the native leaflets close to the main frame.Such configuration achieves numerous goals. For example, suchconfiguration achieves one or more of the following: prevents the nativeleaflets from obstructing flow through the left ventricular outflowtract (LVOT); prevents the native leaflets from interacting with theprosthetic leaflets; recruits the native leaflets in minimizingperi-valvular leaks; maintains proper alignment of the valve prosthesis;avoid systolic anterior mobility; and maintains valve stability bypreventing migration of the valve into the atrium or ventricle andprevents damage to the native chordae. Additionally, the prostheticmitral valve frame can include two or more anchor attachment points.Each anchor attachment point can be attached to one or more anchors thathelp attach the mitral valve to the heart. Such configuration providesadded stability to the prosthetic mitral valve and prevents damage tothe native chordae. The design of the prosthesis also mimics the nativevalve and supports a non-circular in vivo configuration, which betterreflects native valve function.

In view thereof, disclosed herein are aspects of a valve prosthesiswhich is generally designed to include a main frame including a firstsection, a second section, and a third section; a valve body connectedto the frame, and a support frame including a first engagement arm and asecond engagement arm connected to the main frame in the first section,where the first engagement arm is connected to the main frame in thefirst section at a first point and a second point, where in the secondengagement arm is connected to the main frame in the first section at athird point and a fourth point, and where the first engagement arm andthe second engagement arm include a radial portion where the respectivearms extend in the radial direction.

In another exemplary aspect, disclosed herein are aspects of a valveprosthesis which is generally designed to include a valve body and aframe including a first portion connected to the valve body and a secondportion adapted for implantation in a native valve annulus, the framehaving a delivery configuration where the first portion islongitudinally adjacent to the second portion and an expandedconfiguration where the first portion is positioned within an interiorarea of the second portion.

In another exemplary embodiment, disclosed herein are aspects of amethod of treating a valve disorder in a patient's heart which generallyincludes collapsing a valve prosthesis including a frame onto a deliverysystem to place a first portion of the frame adjacent a second portionof the frame, delivering the delivery system and valve prosthesis to aheart, expanding the valve prosthesis in the heart such that the firstportion of the frame moves to be positioned within an interior area ofthe second portion of the frame, and withdrawing the delivery systemfrom the heart.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying figures, which are incorporated herein, form part ofthe specification and illustrate embodiments of a valve prosthesis frameand delivery system. Together with the description, the figures furtherserve to explain the principles of and to enable a person skilled in therelevant art(s) to make, use, and implant the valve prosthesis describedherein. In the drawings, like reference numbers indicate identical orfunctionally similar elements.

FIG. 1 is a perspective view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 2 is a top view of a valve prosthesis frame according to an aspectof this disclosure.

FIG. 3 is a perspective view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 4 is a front view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 5 is a perspective view of a valve prosthesis according to anaspect of this disclosure.

FIG. 6 is a perspective view of a valve prosthesis according to anaspect of this disclosure.

FIG. 7 is a sectional view of a valve prosthesis frame in a collapsedconfiguration according to an aspect of this disclosure.

FIG. 8 is a sectional view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 9 is a schematic view of a valve prosthesis implanted in the heartaccording to an aspect of this disclosure.

FIG. 10 is a front view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 11 is a front view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 12 is a schematic view of a valve prosthesis implanted in the heartaccording to an aspect of this disclosure.

FIG. 13 is an assembly view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 14 is a front view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 15 is a front view of a portion of a valve prosthesis frameaccording to an aspect of this disclosure.

FIG. 16 is an assembly view of a valve prosthesis frame according to anaspect of this disclosure.

FIG. 17 is a front view of a valve prosthesis frame according to anaspect of this disclosure.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description of a valve prosthesis and valveprosthesis frame refers to the accompanying figures that illustrateexemplary embodiments. Other embodiments are possible. Modifications canbe made to the embodiments described herein without departing from thespirit and scope of the present invention. Therefore, the followingdetailed description is not meant to be limiting.

The present invention is directed to a heart valve prosthesis having aself-expanding frame that supports a valve body. The valve prosthesiscan be delivered percutaneously to the heart to replace the function ofa native valve. For example, the valve prosthesis can replace a bicuspidor a tricuspid valve such as the aortic, mitral, pulmonary, or tricuspidheart valve. As used herein the term “distal” is understood to meandownstream to the direction of blood flow. The term “proximal” isintended to mean upstream to the direction of blood flow.

In one aspect of the invention, the valve body comprises three leafletsthat are fastened together at enlarged lateral end regions to formcommissural joints, with the unattached edges forming the coaptationedges of the valve. The leaflets can be fastened to a skirt, which inturn can be attached to the frame. The upper ends of the commissurepoints define an outflow or proximal portion of the valve prosthesis.The opposite end of the valve at the skirt defines an inflow or distalportion of the valve prosthesis. The enlarged lateral end regions of theleaflets permit the material to be folded over to enhance durability ofthe valve and reduce stress concentration points that could lead tofatigue or tearing of the leaflets. The commissural joints are attachedabove the plane of the coaptation edges of the valve body to minimizethe contacted delivery profile of the valve prosthesis. The base of thevalve leaflets is where the leaflet edges attach to the skirt and thevalve frame.

Referring now to FIGS. 1-4, frame 100 is an exemplary aspect of thepresent invention. Frame 100 includes an inner portion 110, an outerportion 120, and connecting arms 130 connecting inner portion 110 toouter portion 120. Inner portion 110 and outer portion 120 in frame 100include a plurality of cells that form a cell pattern. The plurality ofcells can be different sizes and/or shapes.

Inner portion 110 can be configured to be expandable. In one aspect ofthe invention, inner portion 110 is self-expandable and can be formed ofa shape memory alloy such as NITINOL. Other biocompatible metals canalso be used. Outer portion 120 can also be formed of a shape memoryalloy such as NITINOL, or other biocompatible metals. Inner portion 110and outer portion 120 can be integrally formed and connected byconnecting arms 130. Connecting arms 130 can also be formed of a shapememory alloy such as NITINOL, or other biocompatible metals. In analternate aspect of the invention, the inner portion and the outerportion of the frame can comprise separate modular components that areattached to one another, for example as shown in FIG. 17. As shown inFIG. 17, inner portion 5110 is attached to outer portion 5120 byconnections 5130 to form frame 5100.

In one aspect of the invention, inner portion 110 is designed to flexand deform so as to mimic the natural cardiac movements of the heartthrough the cardiac cycle. In another aspect of the invention, innerportion 110 is designed in a rigid fashion to avoid flexing ordeformation during the cardiac cycle.

Frame 100 can be attached to valve 200 to form valve prosthesis 10.Valve 200 can include leaflets 210 and a covering 220. In one aspect ofthe invention, covering 220 is a biocompatible fabric or otherbiocompatible material. In an alternate aspect of the invention,covering 220 can be tissue, for example bovine or porcine pericardium.In one aspect of the invention, valve 200 is connected to frame 100 ininner portion 110. The object of the present valve prosthesis is tomimic the native valve structure. In one aspect of the invention, valve200 can be sewn onto inner portion 110 as described in U.S. PatentApplication Publication No. 2008/0071368, which is incorporated hereinby reference in its entirety. In one aspect of the disclosure, valve 200can be formed of a biocompatible synthetic material, synthetic polymer,an autograft tissue, xenograft tissue, or other alternative materials.In a further aspect of the invention, valve 200 can be a tri-leafletbovine pericardium valve, a bi-leaflet valve, or any other suitablevalve.

Outer portion 120 can be formed in a straight fashion (i.e., cylindricaland parallel to the longitudinal axis of frame 100) or in a flaredfashion (i.e., diverging away from the longitudinal axis of frame 100).In one aspect of the invention, outer portion 120 bulges outward frominner portion 110. In a further aspect of the invention, outer portion120 can be an elliptical shape. In a further aspect, the proximal end ofouter portion 120 is flared outward. In one aspect of the disclosure,outer portion 120 is wider than the native valve at the native valveannulus. Such a configuration prevents migration of prosthesis 10 intothe ventricle and improves sealing of prosthesis 10 against the atrialwall. In an aspect of the invention, outer portion 120 can have anhourglass profile.

In one aspect of the invention, inner portion 110 can be approximately17 mm to approximately 40 mm in diameter. In a further aspect of theinvention, outer portion 120 can be approximately 30 mm to approximately70 mm in diameter.

The plurality of cells forming a cell pattern in frame 100 permit frame100 to adapt to the specific anatomy of the patient, thereby reducingthe risk of valve prosthesis migration and reducing the risk ofperivalvular leakage. In one aspect of the invention, valve prosthesis10 is configured to be disposed in the mitral annulus of a patient'sleft ventricle.

Typically, heart valve prostheses aim to create laminar blood flowthrough the prosthesis in order to prevent lysis of red blood cells,stenosis of the prosthesis, and other thromboembolic complications.Outer portion 120 is designed to conform to a patient's anatomy and toanchor valve prosthesis 10 in the patient's natural valve annulus toprevent lateral movement or migration of valve prosthesis 10 due tonormal movement of the heart.

Inner portion 110 is configured to be expandable and can beself-expandable. Inner portion 110 can be formed of a shape memory alloysuch as NITINOL. Other biocompatible metals can also be used. Outerportion 120 can also be formed of a shape memory alloy such as NITINOL,or other biocompatible metals. Inner portion 110 and outer portion 120can be integrally formed. In this aspect, inner portion 110 is connectedto outer portion 120 with connecting arms 130. In an alternate aspect ofthe invention, inner portion 110 and outer portion 120 can compriseseparate modular components that are attached to one another. In oneaspect of the invention, inner portion 110 is designed to flex anddeform so as to mimic the natural cardiac movements of the heart throughthe cardiac cycle. In another embodiment, inner portion 110 is designedin a rigid fashion to avoid flexing or deformation during the cardiaccycle.

In order to deploy valve prosthesis 10 in a patient's native valve,valve prosthesis 10 can be compacted and loaded onto a delivery devicefor advancement through a patient's vasculature. In the collapsedconfiguration, inner portion 110 and outer portion 120 are positioned inseries such that inner portion 110 is adjacent outer portion 120 alongthe longitudinal axis. FIGS. 3-4 illustrate the relative positioningbetween inner portion 110, outer portion 120 and connecting arms 130 inthe collapsed configuration. In the collapsed configuration, innerportion 110 is longitudinally positioned at a first end of frame 100,outer portion 120 is longitudinally positioned at a second end of frame100, and connecting arms 130 are longitudinally positioned between innerportion 110 and outer portion 120.

Frame 100 is shape set such that upon deployment at a patient's nativevalve annulus, inner portion 110 moves inside outer portion 120 andremains in that position, as shown in FIGS. 1-2 and 6. In an alternateaspect, outer portion 120 moves to surround inner portion 110. In oneaspect of the invention, the entire inner portion 110 is positionedwithin the interior area of outer portion 120. As disclosed herein, theinterior area is defined as the radial and longitudinal space bounded byan inner diameter and a length of a segment of the frame. In thisaspect, the longitudinal length of inner portion 110 is less than orequal to the length of outer portion 120. In an alternate aspect of theinvention, in the expanded configuration, a section of inner portion 110is positioned within the interior area of outer portion 120 and a secondsection of inner portion 110 is positioned outside of the interior areaof outer portion 120. In one aspect of the invention, the longitudinallength of inner portion 110 is greater than the longitudinal length ofouter portion 120. In this aspect, longer inner portion 110 can be usedwith relatively longer valve leaflets so as to increase valve durabilityas compared to a valve prosthesis with shorter valve leaflets.

Positioning inner portion 110 within outer portion 120 reduces theprojection distance of frame 100 into the patient's left ventricle. Ifthe left ventricle of a prosthetic valve is too large, the leftventricle flow tract can become obstructed. This obstruction in turnnegatively affects how blood flows through the heart and into the aorta.Therefore, a low left ventricle projection distance is desired, asprovided by frame 100.

Referring now to FIGS. 7-12, frame 100 can include one or moreengagement arms 310. Engagement arms 310 can be attached to innerportion 110 to anatomically match the native valve leaflets. Uponimplantation, outer engagement arms 310 clamp and immobilize the nativevalve leaflets, and hold the native leaflets close to outer portion 120.As shown in FIG. 9, in one aspect of the disclosure, valve prosthesis 10can be placed in mitral annulus 410. Proper seating of valve prosthesis10 at the mitral annulus 410 is achieved by engagement arms 310capturing the native mitral valve leaflets. The radial force generatedby valve prosthesis 10 in the atrium against engagement arms 310 createsa “sandwich effect” by pinching the native mitral valve leaflets andatrial tissue against outer portion 120 of valve prosthesis 10. Thenative mitral valve leaflet acts as a sealing mechanism around valveprosthesis 10. In addition, engagement arms 310 can add tension onto thenative chordae to reduce peri-valvular leakage and increase valvestability.

In one aspect of the invention, engagement arms 310 are attached toinner portion 110 at connection 320. Each engagement arm can include abend 312, a horizontal component 314, and a second bend 316 in order tobetter match the native valve anatomy. Horizontal component 314 extendsengagement arms 310 in the radial direction. In one aspect of theinvention as shown in FIG. 9, valve prosthesis 10 can include twoengagement arms 310 to capture the native valve leaflets. Engagementarms 310 are connected to each other and to inner portion 110 at acommon point at connection 320.

In a further aspect of the invention shown in FIG. 10, each engagementarm 1310 can be connected to inner portion 1110 at a different pointsuch that frame 1100 includes two connections 1320 for each engagementarm 1310. Attaching each engagement arm 1310 to frame 1100 at differentconnections 1320 reduces the tension imparted onto the native chordae byengagement arms 1310. It is desirable to impart tension onto the nativechordae with valve frame engagement arms. However, excessive tension cancause the native chordae to rupture which reduces the effectiveness ofthe valve prosthesis.

In a further aspect of the invention shown in FIGS. 11-12, frame 2100can have engagement arms of varying lengths in the longitudinaldirection. This varying length of the engagement arms is provided toaccommodate the longer anterior leaflet of the native mitral valve. Inthis aspect, posterior engagement arm 2312 is shorter in thelongitudinal direction than anterior engagement arm 2314. Posteriorengagement arm 2312 and anterior engagement arm 2314 can be connected toframe 2100 at connections 2320 on inner portion 2110. As shown, asection of inner portion 2110 is within an interior area of outerportion 2120.

Referring now to FIGS. 13-15, engagement arms 3310 can includeconnecting segments 3340 that connect the respective connections 3320 toprovide a continuous structure. In this aspect, the continuousengagement arm structure ensures symmetry of engagement arms 3310,simplifies assembly of engagement arms 3310 onto frame 3100, andenhances the overall frame strength. Engagement arms 3310 can alsoinclude additional struts 3350 that extend between connections 3320 ofeach engagement arm 3310. Struts 3350 prevent native valve leaflets frombulging through the engagement arms 3310. In addition, struts 3350 andconnecting segments 3340 can make the resulting valve prosthesisassembly stiffer in the radial direction. The stiffer valve prosthesisis better able to maintain a circular expanded cross section againstfluid pressures exerted on the valve prosthesis. Maintaining a circularcross section provides better valve performance and increases thelongevity of the valve prosthesis.

In a further aspect of the invention, engagement arms 3310, connectingsegments 3340, and additional struts 3350 can be covered with a covering3220. Covering 3220 can be a biocompatible fabric or can be tissue, forexample porcine or bovine pericardium. Covering 3220 can prevent thenative valve leaflets from bulging through engagement arms 3310, canreduce metal to metal abrasion between engagement arms 3310 and frame3100, and can protect the native chordae from abrasion againstengagement arms 3310. In an alternate aspect of the invention, covering3220 only covers engagement arms 3310.

In an alternate aspect of the invention shown in FIG. 16, engagementarms 4313 can be connected to a connecting segment 4340 and can form acontinuous arm structure. Connecting segments 4340 can include a seriesof struts that extend circumferentially and are geometrically identicalin structure to the corresponding struts on frame 4100. In this aspect,engagement arms 4310 can be connected to connecting segment 4340 atconnections 4320. The continuous arm structure provided by connectingsegment 4340 can simplify assembly of the valve prosthesis and enhancesthe overall strength of frame 4100 in the radial direction. In a furtheraspect of the invention, engagement arms 4313 and connecting segment4340 can be covered by a covering (not shown). The covering can be abiocompatible fabric or can be tissue, for example porcine or bovinepericardium.

In a further aspect of the invention, engagement arms can be integrallyformed into the valve prosthesis frame.

Implantation of the valve prosthesis will now be described. As discussedabove, the valve prosthesis preferably comprises a self-expanding framethat can be compressed to a contracted delivery configuration onto adelivery device. This frame design requires a loading system to crimpvalve prosthesis 10 to the delivery size.

The valve prosthesis and inner member can then be loaded into a deliverysheath of conventional design. In one aspect of the invention, valveprosthesis and can be delivered transfemorally. In this aspect, thedelivery device and valve prosthesis can be advanced in a retrogrademanner through the femoral artery and into the patient's descendingaorta. The catheter then is advanced, under fluoroscopic guidance, overthe aortic arch, through the ascending aorta, into the left ventricle,and mid-way across the defective mitral valve. Once positioning of thecatheter is confirmed, the delivery device can deploy valve prosthesis10 in the native annulus.

As the valve prosthesis expands, it traps the leaflets of the patient'sdefective valve against the valve annulus, retaining the native valve ina permanently open state. The outer portion of the valve prosthesisexpands against and aligns the prosthesis within the mitral annulus,while the inner portion withdraws into an interior area of the outerportion to reduce the projection of the valve prosthesis into the leftventricle.

Alternatively, the valve prosthesis can be delivered through atransapical procedure. In a transapical procedure, a trocar or overtubeis inserted into the left ventricle through an incision created in theapex of a patient's heart. A dilator is used to aid in the insertion ofthe trocar. In this approach, the native valve (e.g. the mitral valve)is approached from the downstream relative to the blood flow. The trocaris retracted sufficiently to release the self-expanding valveprosthesis. The dilator is preferably presented between the valveleaflets. The trocar can be rotated and adjusted as necessary toproperly align the valve prosthesis. The dilator is advanced into theleft atrium to begin disengaging the proximal section of the valveprosthesis from the dilator. In the transapical procedure, the innerportion of the frame can be inserted first and the outer portion canthen be moved distally such that it sits at the mitral annulus. In thisconfiguration, the back pressure of blood flow from the left ventriclewon't cause the inner portion of the frame to be pushed back into itsoriginal configuration where the inner portion and outer portion arelongitudinally adjacent to each other.

In an alternate aspect of the invention, the valve prosthesis can bedelivered through a transatrial procedure. In this procedure, thedilator and trocar are inserted through an incision made in the wall ofthe left atrium of the heart. The dilator and trocar are advancedthrough the native valve and into the left ventricle of heart. Thedilator is then withdrawn from the trocar. A guide wire is advancedthrough the trocar to the point where the valve prosthesis comes to theend of the trocar. The valve prosthesis is advanced sufficiently torelease the self-expanding frame from the trocar. The trocar can berotated and adjusted as necessary to properly align the valveprosthesis. The trocar is completely withdrawn from the heart such thatthe valve prosthesis self-expands into position and assumes the functionof the native valve.

The foregoing description has been presented for purposes ofillustration and enablement, and is not intended to be exhaustive or tolimit the invention to the precise form disclosed. Other modificationsand variations are possible in light of the above teachings. Theembodiments and examples were chosen and described in order to bestexplain the principles of the invention and its practical applicationand to thereby enable others skilled in the art to best utilize theinvention in various embodiments and various modifications as are suitedto the particular use contemplated. It is intended that the appendedclaims be construed to include other alternative embodiments of theinvention.

What is claimed is:
 1. A valve prosthesis comprising: a main frameincluding a first inner section and a second outer section that areconnected to each other by a third connector section such that the firstinner section is at least partially positioned within and overlapped bythe second outer section when the main frame is in an expandedconfiguration; a valve body connected to the first inner section of themain frame; and a support frame including a first engagement arm and asecond engagement arm, wherein the support frame is a continuousstructure with the first and second engagement arms being integralthereto, the support frame being connected to the first inner section ofthe main frame such that, a first end of the first engagement arm isconnected to the main frame in the first inner section at a first pointand a second end of the first engagement arm is connected to the mainframe in the first inner section at a second point, and a first end ofthe second engagement arm is connected to the main frame in the firstinner section at a third point and a second end of the second engagementarm is connected to the main frame in the first inner section at afourth point.
 2. The valve prosthesis of claim 1, wherein a length ofthe first engagement arm in the longitudinal direction is equal to alength of the second engagement arm in the longitudinal direction. 3.The valve prosthesis of claim 1, wherein a length of the firstengagement arm in the longitudinal direction is greater than a length ofthe second engagement arm in the longitudinal direction.
 4. The valveprosthesis of claim 1, wherein the first point is equal to the fourthpoint, and wherein the second point is equal to the third point.
 5. Thevalve prosthesis of claim 1, wherein the first point, second point,third point, and fourth point are distinct.
 6. The valve prosthesis ofclaim 1, wherein the support frame further includes a first connectingsegment joining the first engagement arm at the first point to thesecond engagement arm at the fourth point, and a second connectingsegment joining the first engagement arm at the second point to thesecond engagement arm at the third point.
 7. The valve prosthesis ofclaim 6, wherein the support frame further includes a biocompatiblematerial covering the first engagement arm, the second engagement arm,the first connecting segment, and the second connecting segment.
 8. Thevalve prosthesis of claim 6, wherein the first and second connectingsegments of the support frame have a radially repeating cell pattern. 9.The valve prosthesis of claim 8, wherein the radially repeating cellpattern of the first and second connecting segments is identical to theradially repeating cell pattern of the first inner section.
 10. Thevalve prosthesis of claim 8, wherein the support frame further includesa biocompatible material covering the first engagement arm, the secondengagement arm, the first connecting segment, and the second connectingsegment.
 11. The valve prosthesis of claim 1, wherein the firstengagement arm is distinct from the second engagement arm.
 12. The valveprosthesis of claim 1, wherein the first engagement arm and the secondengagement arm extend outward from the main frame to form a gap betweena free end of the first engagement arm and the main frame and between afree end of the second engagement arm and the main frame.
 13. The valveprosthesis of claim 1, wherein a free end of the first engagement armand a free end of the second engagement arm conform to an exteriorsurface of the main frame.
 14. The valve prosthesis of claim 1, whereinthe third connector section is comprised of a plurality of connectingarms with first ends of the plurality of connecting arms being attachedto the first inner section and with second ends of the plurality ofconnecting arms being attached to the second outer section.